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/*
Crown Copyright (c) 1997
This TenDRA(r) Computer Program is subject to Copyright
owned by the United Kingdom Secretary of State for Defence
acting through the Defence Evaluation and Research Agency
(DERA). It is made available to Recipients with a
royalty-free licence for its use, reproduction, transfer
to other parties and amendment for any purpose not excluding
product development provided that any such use et cetera
shall be deemed to be acceptance of the following conditions:-
(1) Its Recipients shall ensure that this Notice is
reproduced upon any copies or amended versions of it;
(2) Any amended version of it shall be clearly marked to
show both the nature of and the organisation responsible
for the relevant amendment or amendments;
(3) Its onward transfer from a recipient to another
party shall be deemed to be that party's acceptance of
these conditions;
(4) DERA gives no warranty or assurance as to its
quality or suitability for any purpose and DERA accepts
no liability whatsoever in relation to any use to which
it may be put.
*/
/**********************************************************************
$Author: release $
$Date: 1998/01/17 15:56:06 $
$Revision: 1.1.1.1 $
$Log: regexps.c,v $
* Revision 1.1.1.1 1998/01/17 15:56:06 release
* First version to be checked into rolling release.
*
* Revision 1.7 1996/01/25 17:07:21 currie
* Alias with bit-fields
*
* Revision 1.6 1996/01/08 17:05:33 currie
* current_env in depends_on
*
* Revision 1.5 1995/10/20 10:48:03 currie
* avs -slow + attempts to cheat buggy scheduler
*
* Revision 1.4 1995/09/12 10:59:41 currie
* gcc pedanttry
*
* Revision 1.3 1995/09/04 10:11:57 currie
* e changes !
*
* Revision 1.2 1995/08/16 16:07:08 currie
* Shortened some .h names
*
* Revision 1.1 1995/04/13 09:08:06 currie
* Initial revision
*
***********************************************************************/
/* regexps.c
For trivial 'peephole' optimisations
*/
#include "config.h"
#include "expmacs.h"
#include "addrtypes.h"
#include "tags.h"
#include "move.h"
#include "bitsmacs.h"
#include "maxminmacs.h"
#include "shapemacs.h"
#include "common_types.h"
#include "extratags.h"
#include "check.h"
#include "basicread.h"
#include "regexps.h"
regpeep regexps[48]; /* [0:31] fix pt - [32:47] floating pt */
bool sim_exp PROTO_S ((exp a, exp b));
bool eq_sze
PROTO_N ( (as, bs) )
PROTO_T ( shape as X shape bs )
{
if (is_floating(name(as))) return(name(as)==name(bs));
if (is_floating(name(bs))) return 0;
return (shape_size(as) == shape_size(bs) && shape_align(as)==shape_align(bs));
}
bool sim_explist
PROTO_N ( (al, bl) )
PROTO_T ( exp al X exp bl )
{
if (al == nilexp && bl == nilexp)
return (1);
if (al == nilexp || bl == nilexp)
return (0);
if (!sim_exp (al, bl))
return (0);
if (last (al) && last (bl))
return (1);
if (last (al) || last (bl))
return (0);
return (sim_explist (bro (al), bro (bl)));
}
bool sim_exp
PROTO_N ( (a,b) )
PROTO_T ( exp a X exp b )
{ /* basically eq_exp except equal shapes
requirement is weakened to equal sizes
and alignments */
if (name (a) == name (b)) {
if (name (a) == name_tag)
return (son (a) == son (b) && no (a) == no (b) &&
eq_sze (sh (a), sh (b)));
if (name(a)==maxlike_tag || name(a)==minlike_tag || name(a)==abslike_tag) {
return (props(son(a))==props(son(b)) &&
shape_size(sh(a))==shape_size(sh(b)) &&
sim_explist(son(son(a)),son(son(b)) ) );
}
if (!is_a (name (a)) || !eq_sze (sh (a), sh (b)))
return (0);
if (name(a) == float_tag) return eq_exp(son(a), son(b));
return (no (a) == no (b) &&
sim_explist (son (a), son (b)));
};
return (0);
}
void clear_all
PROTO_Z ()
{ /* forget all register - exp associations */
int i;
for (i = 0; i < 48; i++) {
regexps[i].keptexp = nilexp;
setregalt (regexps[i].inans, 0);
}
}
void clear_reg
PROTO_N ( (i) )
PROTO_T ( int i )
{ /* forget reg i - exp association */
i = abs (i);
if (i >= 0 && i < 48) {
regexps[i].keptexp = nilexp;
setregalt (regexps[i].inans, 0);
}
}
ans iskept
PROTO_N ( (e) )
PROTO_T ( exp e )
{ /* find if e has already been evaluated
into a register */
int i;
ans nilans;
ans aa;
setregalt (nilans, 0);
aa = nilans;
for (i = 0; i < 48; i++) {
exp ke = regexps[i].keptexp;
bool isc = regexps[i].iscont;
if (ke != nilexp) { /* there is an accociation with reg i */
if (
((!isc && sim_exp (ke, e)) ||
(name (e) == cont_tag && isc &&
eq_sze (sh (ke), sh (e))
&& sim_exp (ke, son (e)) && al1(sh(son(e))) == al1(sh(ke)) )
)
) {
aa = (regexps[i].inans);
switch (aa.discrim) {
case notinreg:
{
if (!aa.val.instoreans.adval) {
/* the expression is given indirectly - it
may have also been loaded into a
register */
continue;
}
/* else ... */
}
default:
return aa;
}
}
else
if (name (ke) == cont_tag && !isc) {
ans aq;
aq = regexps[i].inans;
if (aq.discrim == notinreg) {
instore is;
is = insalt (aq);
if (!is.adval && is.b.offset == 0 && is.b.base > 0 && is.b.base < 31
&& sim_exp (son (ke), e)) {
/* the contents of req expression is here
as a reg-offset */
is.adval = 1;
setinsalt (aq, is);
return aq;
}
}
}
else
if (name (ke) == reff_tag && !isc) {
ans aq;
aq = regexps[i].inans;
if (aq.discrim == notinreg) {
instore is;
is = insalt (aq);
if (is.adval && is.b.offset == (no (ke) / 8)
&& is.b.base > 0 && is.b.base < 31
&& sim_exp (son (ke), e)) {
/* a ref select of req expression is here
as a reg-offset */
is.adval = 1;
is.b.offset = 0;
setinsalt (aq, is);
return aq;
}
}
}
}
}
return aa;
}
void keepexp
PROTO_N ( (e, loc) )
PROTO_T ( exp e X ans loc )
{ /* set up exp - address association */
int pos;
switch (loc.discrim) {
case insomereg:
case insomefreg: {
failer ("Keep ? reg");
}
case inreg:
{
pos = regalt (loc);
break;
}
case infreg:
{
pos = fregalt (loc).fr + 32;
break;
}
case notinreg:
{
pos = insalt (loc).b.base;
if (pos < 0 || pos > 30)
return;
}
};
if (pos==2 || pos == 32) return;
regexps[pos].keptexp = e;
regexps[pos].inans = loc;
regexps[pos].iscont = 0;
}
void keepcont
PROTO_N ( (e, reg) )
PROTO_T ( exp e X int reg )
{/* set up cont(e)-reg association */
freg fr;
int z = abs (reg);
if (z==2|| z==32) return;
if (z > 31) {
fr.dble = (reg < 0);
fr.fr = z - 32;
setfregalt (regexps[z].inans, fr);
}
else {
instore is;
is.b.base = reg;
is.b.offset = 0;
is.adval = 1;
setinsalt (regexps[z].inans, is);
}
regexps[z].keptexp = e;
regexps[z].iscont = 1;
}
void keepreg
PROTO_N ( (e, reg) )
PROTO_T ( exp e X int reg )
{ /* set up e-reg association */
freg fr;
int z = abs (reg);
if (z==2 || z==32) return;
if (z > 31) {
fr.dble = (reg < 0);
fr.fr = z - 32;
setfregalt (regexps[z].inans, fr);
}
else {
instore is;
is.b.base = reg;
is.b.offset = 0;
is.adval = 1;
setinsalt (regexps[z].inans, is);
}
regexps[z].keptexp = e;
regexps[z].iscont = 0;
}
static bool couldeffect PROTO_S ((exp e, exp z, int count));
static bool couldbe
PROTO_N ( (e, lhs, count) )
PROTO_T ( exp e X exp lhs X int count )
{ /* could e be lhs? */
int ne = name (e);
exp s = son (e);
if (ne == name_tag) {
if (lhs != 0 && s == son (lhs)) {
return 1;
}
if (isvar (s)) {
return (lhs == 0 && (isvis (s) || isglob(s)));
}
if (name (s) == proc_tag)
return (lhs == 0);
if (son (s) == nilexp)
return 1;
if (count > 5) return 1; /* pathological */
return couldbe (son (s), lhs, count+1);
}
if (ne == cont_tag) {
if (lhs != 0 && name (s) == name_tag && son (s) != nilexp) {
return (son (s) == son (lhs) || isvis (son (lhs)) || isvis (son (s)));
}
return 1;
}
if (ne == reff_tag || ne == field_tag) {
return couldbe (s, lhs, count);
}
if (ne == addptr_tag || ne == subptr_tag) {
return (couldbe (s, lhs, count) || couldeffect (bro (s), lhs, count));
}
return 1;
}
static bool couldeffect
PROTO_N ( (e, z, count) )
PROTO_T ( exp e X exp z X int count )
{
/* could alteration to z effect e? */
int ne = name (e);
if (ne == cont_tag) {
return couldbe (son (e), z, count);
}
if (ne == name_tag) {
if (isvar (son (e)))
return (z == 0 && isvis (son (e)));
if (name (son (e)) == proc_tag)
return 0;
if (son (son (e)) == nilexp)
return 1 /* could it happen? */ ;
if (count > 5) return 1; /* pathological */
return couldeffect (son (son (e)), z, count+1);
}
if (ne < plus_tag || ne == contvol_tag)
return 1;
e = son (e);
while (e != nilexp) {
if (couldeffect (e, z, count))
return 1;
if (last (e))
return 0;
e = bro (e);
}
return 0;
}
bool dependson
PROTO_N ( (e, isc, z) )
PROTO_T ( exp e X bool isc X exp z )
{/* does e depend on z */
if (e == nilexp) {
return 0;
}
for (;;) {
if (name (z) == reff_tag || name (z) == addptr_tag ||
name (z) == subptr_tag) {
z = son (z);
}
if (name (z) != name_tag) {
if (name (z) != cont_tag)
return 1;
z = 0;
break;
}
if (isvar (son (z)))
break;
if (name (son (z)) == proc_tag) {
z = 0;
break;
}
if (son (son (z)) == nilexp)
return 1; /* can it happen? */
z = son (son (z));
}
/* z is now unambiguous variable name or 0 meaning some contents */
return ((isc) ? couldbe (e, z, 0) : couldeffect (e, z, 0));
}
void clear_dep_reg
PROTO_N ( (lhs) )
PROTO_T ( exp lhs )
{ /* remove association of any register
which depends on lhs */
int i;
for (i = 0; i < 48; i++) {
if (dependson (regexps[i].keptexp, regexps[i].iscont, lhs)) {
regexps[i].keptexp = nilexp;
setregalt (regexps[i].inans, 0);
}
}
}